In a,hopefully futile, effort to confuse programmers, the use
directive, was given a second job to do. It turns other compiler
directives on and off. For example, you might want to force Perl
to use integer math instead of floating-point match to speed up
certain sections of your program.

Remember all of the new terminology that was developed for objects?
The computer scientists have also developed their own term for
a compiler directive. And that term is Pragma. The use
statement controls the other pragmas.

The listing below shows a program
that uses the integer pragma integer.pl: